FLARM - No GPS

On Fri, 25 Nov 2016 18:33:43 -0700, Dan Marotta wrote:

If there was GPS jamming it would have affected the ClearNav and the
Streak, wouldn't it?

Today I removed the unit from the aluminum plate, reloaded the latest
firmware, performed a factory reset and - it still did not work. I had
the unit removed from the ship and had replaced the external antennae
with the rubber duckies. Yes, they were connected to the proper inputs.

The log file appears to show a proper start up with no faults. So where
do I go from here?

Here's a quick list of the interesting stuff in the IGC logs written by
FLARM equipment. This comes from one of my Red Box FLARM logs but a PF
should log much the same data.

The first character on each line in the log is always the record type, so
in the following I refer to a line starting with A as the 'A record'.

The GPS type should be given by an H record. These are grouped together
and should immediately follow the A record. There are typically 10-15 H
records (my Red Box FLARM outputs 14). The one starting with "HFGPS"
gives the GPS type details preceded by the characters "HFGPS" and filling
the rest of the line.

If the GPS is working the log should include an F record from time to
time. This lists the navigation satellites (GPS, Glonass or Gallileo)
that the GPS can see. A new F record is written each time the set of
visible satellites changes. For what you're trying to find out, the F
record just confirms that your PF is seeing satellites

Apart from this, the rest of my Red Box logs are mainly B and L records.

Each B record is a 3D point showing where the glider is at the time the
record was written - no GPS signal means you won't see these in the log.

L records are proprietary to FLARM. AFAIK their formats are not
published so I don't know what they contain. However, its an easy guess
that their contents includes the data used by the FLARM range analysis
tool, i.e. the range and bearings of any other FLARM units yours is
talking to.

I hope the above is some use to you.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |